1. Field of the Invention
The present disclosure relates to a method for fabricating a semiconductor device, and more particularly, to a method for fabricating a semiconductor device having a variable resistance layer which switches between two or more different resistance states as the resistance thereof is changed according to an applied voltage or current.
2. Description of the Related Art
A variable resistance memory device, of which resistance is changed according to an external stimulus, switches between two or more resistance states so as to store data. Variable resistance memory devices include, for example, a resistive random access memory (ReRAM), a phase change RAM (PCRAM), a spin transfer torque-RAM (STT-RAM), and the like. Critically, variable resistance memory devices have a simple structure yet provide a number of desirable characteristics such as nonvolatility. Thus, a large amount of research has been conducted on variable resistance memory devices.
Among variable resistance memory devices, ReRAM has a structure that includes a variable resistance material, for example, a variable resistance layer formed of a perovskite-based material or transition metal oxide, and electrodes over and under the variable resistance layer. When a voltage is applied to the electrodes, a filament-shaped current path is formed or is absent in the variable resistance layer. Thus, when the filament-shaped current path is formed, the variable resistance layer is set in a low resistance state, and when the filament-shaped current path is absent, the variable resistance layer is set in a high resistance state.